EP3318467A1 - Steering system - Google Patents

Steering system Download PDF

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Publication number
EP3318467A1
EP3318467A1 EP17199697.8A EP17199697A EP3318467A1 EP 3318467 A1 EP3318467 A1 EP 3318467A1 EP 17199697 A EP17199697 A EP 17199697A EP 3318467 A1 EP3318467 A1 EP 3318467A1
Authority
EP
European Patent Office
Prior art keywords
housing
axial direction
elastic support
support portion
driven pulley
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP17199697.8A
Other languages
German (de)
English (en)
French (fr)
Inventor
Masashi Yamaguchi
Tetsuya Kaneko
Shuhei Yamashita
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JTEKT Corp
Original Assignee
JTEKT Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by JTEKT Corp filed Critical JTEKT Corp
Publication of EP3318467A1 publication Critical patent/EP3318467A1/en
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D3/00—Steering gears
    • B62D3/02—Steering gears mechanical
    • B62D3/04—Steering gears mechanical of worm type
    • B62D3/06—Steering gears mechanical of worm type with screw and nut
    • B62D3/08—Steering gears mechanical of worm type with screw and nut using intermediate balls or the like
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D3/00—Steering gears
    • B62D3/02—Steering gears mechanical
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B62D5/0421—Electric motor acting on or near steering gear
    • B62D5/0424—Electric motor acting on or near steering gear the axes of motor and final driven element of steering gear, e.g. rack, being parallel
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B62D5/0442—Conversion of rotational into longitudinal movement
    • B62D5/0445—Screw drives
    • B62D5/0448—Ball nuts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D5/00—Power-assisted or power-driven steering
    • B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
    • B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
    • B62D5/046—Controlling the motor
    • B62D5/0463—Controlling the motor calculating assisting torque from the motor based on driver input
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
    • B62D6/08—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits responsive only to driver input torque
    • B62D6/10—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits responsive only to driver input torque characterised by means for sensing or determining torque

Definitions

  • an automotive steering system configured to generate a thrust in an axial direction of a steering operation shaft by a motor as described in Japanese Patent Application Publication No. 2014-227047 ( JP 2014-227047 A ).
  • a ball screw shaft is formed on the outer peripheral surface of the steering operation shaft to which steered wheels are coupled on both sides via tie rods and the like.
  • a ball nut threadedly engages with the ball screw shaft via balls.
  • the ball nut is coupled to a toothed driven pulley in the axial direction, and the driven pulley is connected to a toothed driving pulley by a belt.
  • the toothed driving pulley is fixed to an output shaft of the motor.
  • the outer ring of the bearing moves slightly in the axial direction relative to the housing against the elastic force of the elastic support portion, and the steered wheels are turned from their neutral positions. Therefore, when the driver operates the steering wheel that is set at the neutral position, a quick initial response is obtained in the steering operation for the steered wheels that are set at the neutral positions.
  • the ball screw shaft, the ball nut, the bearing, and the elastic support portions are assembled into a subassembly in advance, and this subassembly is mounted on the housing.
  • the elastic support portion may fall off the subassembly when the subassembly is mounted on the housing.
  • a steering system includes a steering operation shaft, a ball screw mechanism, a motor, a driving pulley, a driven pulley, an annular toothed belt, a housing, a bearing, a first elastic support portion, a second elastic support portion, a first retaining member, and a second retaining member.
  • the steering operation shaft is configured to move in an axial direction to turn a steered wheel.
  • the ball screw mechanism includes a ball screw shaft formed on an outer peripheral surface of the steering operation shaft, and a ball nut threadedly engaging with the ball screw shaft via a plurality of balls.
  • the motor is configured to output a rotational torque. The rotational torque output from the motor is transmitted to the driving pulley.
  • the driven pulley is provided on the ball nut so as to be rotatable together with the ball nut.
  • the toothed belt is configured to transmit the rotational torque between the driving pulley and the driven pulley.
  • the housing houses the steering operation shaft, the ball screw mechanism, and the driven pulley and has a first locking surface and a second locking surface facing each other in the axial direction.
  • the bearing includes an inner ring fitted to the ball nut or the driven pulley, and an outer ring provided on an outer peripheral side of the inner ring so as to be rotatable relative to the inner ring and to be movable in the axial direction relative to the housing between the first locking surface and the second locking surface.
  • the first elastic support portion is formed into an annular shape, provided between the first locking surface and one end face of the outer ring, and configured to elastically support the outer ring in the axial direction.
  • the second elastic support portion is formed into an annular shape, provided between the second locking surface and the other end face of the outer ring, and configured to elastically support the outer ring in the axial direction.
  • the first retaining member is formed into an annular shape and configured to fix the inner ring to the ball nut or the driven pulley and to lock the first elastic support portion.
  • the second retaining member is formed into an annular shape, provided on the ball nut or the driven pulley as a unit, and configured to lock the second elastic support portion.
  • a steering system S1 includes a steering mechanism 10, a steering operation mechanism 20, a steering assist mechanism 30, and a torque detection device 40.
  • the steering operation shaft 21 has joints 27 and 28 at its both ends.
  • the joints 27 and 28 are formed such that the diameter of the steering operation shaft 21 is increased at its both ends.
  • Tie rods 24 and 24 are coupled to both ends of the joints 27 and 28, and the distal ends of the tie rods 24 and 24 are coupled to knuckles (not illustrated) on which the steered wheels 26 are mounted.
  • the rotation of the pinion shaft 15 is converted by the pinion teeth 15d and the rack teeth 21a into movement of the steering operation shaft 21 along the axial direction A (linear reciprocal movement). Therefore, the steering operation shaft 21 moves along the axial direction A.
  • the movement of the steering operation shaft 21 along the axial direction A is transmitted to the knuckles (not illustrated) via the tie rods 24 and 24, thereby turning the steered wheels 26 and 26.
  • the traveling direction of a vehicle is changed.
  • the torque detection device 40 is fixed to an attachment opening 22c of the housing 22 that is located around the pinion shaft 15.
  • the torque detection device 40 detects a torsion amount of the torsion bar 15c, and outputs a signal in accordance with the torsion amount to a control unit ECU.
  • the torsion bar 15c herein refers to a member having such a characteristic as to be twisted in accordance with a difference between a torque of the input shaft 15a and a torque of the output shaft 15b.
  • the second housing 22a includes a second tubular portion 221 having a cylindrical shape, the second steering assist housing 222 formed on the first housing 22b side of the second tubular portion 221, and a wall portion 224 (illustrated in FIG. 3 ) that connects the second tubular portion 221 and the second steering assist housing 222 to each other and is formed in a direction orthogonal to the axial direction A.
  • the second tubular portion 221 is a housing portion that mainly houses the steering operation shaft 21.
  • the second steering assist housing 222 is a portion that mainly houses the devices relating to the steering assist mechanism 30.
  • a locking protrusion 222b is formed so as to protrude from the outer peripheral surface of the second steering assist housing 222.
  • the face of the locking protrusion 222b on the first side in the axial direction A includes an abutment surface 222c extending in a direction orthogonal to the axial direction A.
  • the end of the first steering assist housing 232 on the second side in the axial direction A is provided on an outer peripheral side of the end of the second steering assist housing 222 on the first side in the axial direction A so as to overlap this end of the second steering assist housing 222.
  • the end face of the first steering assist housing 232 on the second side in the axial direction A abuts against the abutment surface 222c of the second steering assist housing 222.
  • the third housing 31 is fixed via a plate 36 to a bulging end face 223 of the second steering assist housing 222, which is formed in a direction orthogonal to the axial direction A from the wall portion 224 (illustrated in FIG. 3 ).
  • the surface of the third housing 31 that faces the bulging end face 223 of the second steering assist housing 222 has an opening 311.
  • the opening 311 is closed by the plate 36.
  • the plate 36 has a through hole 36a through which an output shaft 32b of the motor M is inserted in the axial direction A.
  • the electric device MCU including the motor M is housed in the third housing 31.
  • the rotary shaft 32 is an output shaft of the motor M, and transmits the rotational torque output from the motor M.
  • the rotary shaft 32 includes the output shaft 32b and a driving pulley 32a arranged on an outer peripheral side of the output shaft 32b.
  • the output shaft 32b is rotatably supported at the through hole 36a of the plate 36 via a bearing 313.
  • a part of the output shaft 32b extends from the inside of the third housing 31 toward the second steering assist housing 222 of the housing 22 that is located outside the third housing 31, and is housed in the second steering assist housing 222.
  • the driving pulley 32a is provided on the outer peripheral surface of the output shaft 32b at a part located outside the third housing 31 in the axial direction A. The rotational torque generated by the motor M is transmitted to the driving pulley 32a.
  • This structure restricts movement of the toothed belt 35a in the axial direction A, thereby preventing the toothed belt 35a from falling off the toothing 34b.
  • a first surface of the flange portion 38b of the guide portion 38 (second retaining member) on the first side in the axial direction A faces a holding member 62 of a second elastic support portion 65, and a second surface of the flange portion 38b faces the end face of the toothed belt 35a.
  • the inner peripheral surface of the first steering assist housing 232 includes an outer ring sliding surface 232a having a bore diameter larger than that of the other part.
  • the outer ring 37b is provided on an inner peripheral side of the outer ring sliding surface 232a.
  • the outer peripheral surface of the outer ring 37b and the outer ring sliding surface 232a are fitted to each other by clearance fit.
  • a first elastic support portion 60 is provided between the first locking surface 232b and the end face of the outer ring 37b on the first side in the axial direction A.
  • the second elastic support portion 65 is provided between the second locking surface 222d and the end face of the outer ring 37b on the second side in the axial direction A.
  • the first elastic support portion 60 and the second elastic support portion 65 urge the outer ring 37b toward the center of its movement range by supporting (elastically supporting) the outer ring 37b so as to be elastically movable in the axial direction A.
  • Each of the first elastic support portion 60 and the second elastic support portion 65 is constituted by an urging member 61 and a holding member 62.
  • the movement of the steering operation shaft 21 in the axial direction A does not involve the rotation of the ball nut 33a.
  • the steered wheels 26 and 26 are turned from their neutral positions. Therefore, when the driver operates the steering wheel 11 that is set at the neutral position, a quick initial response is obtained in the steering operation for the steered wheels 26 and 26 that are set at the neutral positions.
  • the holding portion 62b of the holding member 62 restricts displacement of the urging member 61 in the gravity direction (direction orthogonal to the axial direction A). Therefore, misalignment of the urging member 61 in the gravity direction is prevented.
  • the outer ring 37b of the bearing 37 can securely be urged toward the central position of its movement range by the urging force of the urging member 61.
  • the anti-wear portion 62a of the holding member 62 is located between the urging member 61 and the first locking surface 232b or the second locking surface 222d of the housing 22.
  • the second elastic support portion 65 assembled into the subassembly SA is locked by the guide portion 38 (second retaining member) on the first side in the axial direction A, thereby preventing the second elastic support portion 65 from falling off the subassembly SA.
  • the steering system S1 includes the steering operation shaft 21, the ball screw mechanism 33, the motor M, the driving pulley 32a, the driven pulley 34, the annular toothed belt 35a, the housing 22, the bearing 37, the first elastic support portion 60, the second elastic support portion 65, the retaining member 71 (first retaining member), and the guide portion 38 (second retaining member).
  • the steering operation shaft 21 is configured to move in the axial direction A to turn the steered wheels 26 and 26.
  • the ball screw mechanism 33 includes the ball screw shaft 21b formed on the outer peripheral surface of the steering operation shaft 21, and the ball nut 33a threadedly engaging with the ball screw shaft 21b via the plurality of balls 33b.
  • the motor M is configured to output a rotational torque.
  • the rotational torque output from the motor M is transmitted to the driving pulley 32a.
  • the driven pulley 34 is provided on the ball nut 33a so as to be rotatable together with the ball nut 33a.
  • the toothed belt 35a is configured to transmit the rotational torque between the driving pulley 32a and the driven pulley 34.
  • the housing 22 houses the steering operation shaft 21, the ball screw mechanism 33, and the driven pulley 34 and has the first locking surface 232b and the second locking surface 222d facing each other in the axial direction A.
  • the second elastic support portion 65 is formed into an annular shape, provided between the second locking surface 222d and the other end face of the outer ring 37b, and configured to elastically support the outer ring 37b in the axial direction A.
  • the retaining member 71 (first retaining member) is formed into an annular shape, removably provided on the driven pulley 34, and configured to fix the inner ring 37a to the driven pulley 34 and to lock the first elastic support portion 60.
  • the guide portion 38 (second retaining member) is formed into an annular shape, provided on the driven pulley 34 as a unit, and configured to lock the second elastic support portion 65.
  • the retaining member 71 (first retaining member) is an internally threaded nut member threadedly attached to the driven pulley 34.
  • the internally threaded nut member configured to fix the inner ring 37a to the driven pulley 34 and threadedly attached to the driven pulley 34 is used as the retaining member 71 (first retaining member). Therefore, the structure capable of preventing the first elastic support portion 60 from falling off the subassembly SA can be attained by simply forming the protruding portion 71b on the internally threaded nut member that exists hitherto. As a result, the steering system S1 in which the first elastic support portion 60 can be prevented from falling off the subassembly SA can be provided while suppressing an increase in cost, weight, and size.
  • the structure capable of preventing the second elastic support portion 65 from falling off the subassembly SA can be attained by the guide portion 38 that exists hitherto.
  • the steering system S1 in which the second elastic support portion 65 can be prevented from falling off the subassembly SA can be provided while suppressing an increase in cost, weight, and size.
  • the housing 22 includes the first housing 22b formed into a tubular shape and having the first locking surface 232b formed on its inner peripheral surface, and the second housing 22a formed into a tubular shape, coupled to the first housing 22b while closing the opening of the first housing 22b, and having the second locking surface 222d formed on the end face in the axial direction A.
  • the subassembly SA is mounted on the first housing 22b, and the second housing 22a is attached to the first housing 22b so as to close the opening of the first housing 22b.
  • the subassembly SA can be housed in and mounted on the second housing 22a and the first housing 22b while preventing the first elastic support portion 60 and the second elastic support portion 65 from falling off the subassembly SA.
  • the urging member 61 is a disc spring.
  • the urging member 61 may be a wave washer or a rubber member having a circular ring shape.
  • the guide portion 38 is provided separately from the driven pulley 34. There may be employed an embodiment in which the guide portion 38 is provided integrally with the driven pulley 34.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Power Steering Mechanism (AREA)
  • Transmission Devices (AREA)
  • Rolling Contact Bearings (AREA)
EP17199697.8A 2016-11-04 2017-11-02 Steering system Withdrawn EP3318467A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2016216557A JP2018070117A (ja) 2016-11-04 2016-11-04 ステアリング装置

Publications (1)

Publication Number Publication Date
EP3318467A1 true EP3318467A1 (en) 2018-05-09

Family

ID=60244937

Family Applications (1)

Application Number Title Priority Date Filing Date
EP17199697.8A Withdrawn EP3318467A1 (en) 2016-11-04 2017-11-02 Steering system

Country Status (4)

Country Link
US (1) US20180127019A1 (ja)
EP (1) EP3318467A1 (ja)
JP (1) JP2018070117A (ja)
CN (1) CN108016487A (ja)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20190382047A1 (en) * 2017-01-20 2019-12-19 Hitachi Automotive Systems, Ltd. Power steering apparatus
KR102098053B1 (ko) * 2018-09-20 2020-04-07 주식회사 만도 랙구동형 동력 보조 조향장치
JP2021076178A (ja) 2019-11-07 2021-05-20 日本精工株式会社 動力伝達装置
JP2021076177A (ja) 2019-11-07 2021-05-20 日本精工株式会社 動力伝達装置
KR20210152644A (ko) * 2020-06-09 2021-12-16 주식회사 만도 자동차의 조향장치
CN113147885B (zh) * 2021-05-07 2022-08-05 徐州重型机械有限公司 一种双回路半整体式转向器、转向助力系统及起重机

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014227047A (ja) 2013-05-22 2014-12-08 株式会社ジェイテクト 電動パワーステアリング装置
WO2016125368A1 (ja) * 2015-02-03 2016-08-11 株式会社ジェイテクト ステアリング装置
EP3252344A1 (en) * 2016-05-30 2017-12-06 Jtekt Corporation Ball screw device and steering system
EP3255310A1 (en) * 2016-06-03 2017-12-13 Jtekt Corporation Ball screw device and steering system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014227047A (ja) 2013-05-22 2014-12-08 株式会社ジェイテクト 電動パワーステアリング装置
WO2016125368A1 (ja) * 2015-02-03 2016-08-11 株式会社ジェイテクト ステアリング装置
EP3254930A1 (en) * 2015-02-03 2017-12-13 Jtekt Corporation Steering device
EP3252344A1 (en) * 2016-05-30 2017-12-06 Jtekt Corporation Ball screw device and steering system
EP3255310A1 (en) * 2016-06-03 2017-12-13 Jtekt Corporation Ball screw device and steering system

Also Published As

Publication number Publication date
US20180127019A1 (en) 2018-05-10
CN108016487A (zh) 2018-05-11
JP2018070117A (ja) 2018-05-10

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